It's a science, actually, but most who aren't familiar with it tend to think it's some sort of magic. It's not looked highly upon to refer to it as such in Amestris; I'll have to ask you to refrain from doing so, if you don't mind.

[He doesn't sound offended, however; he's gotten that more than enough here to get offended over it anymore.]

As for how long I've been at it, I've been capable since I was a child. However, I didn't start to actually hone my craft until I was a teenager, which is a fairly late start, as things go back in my world.